So I'd look for pre-war types operating in the region as a possible source and try to elminate from there.
Remember. To qualify as an alternative source for 2-2-V-1 we need an American pre-war type that used #3 rivets in a .032 ALCLAD skin - and it has to have been repaired and then later destroyed in a way consistent with the damage we see on the artifact.
First, let's list all known pre-war (prior to December 1941) aviation activity at or near Gardner Island. It's a short list.
July 9, 1937 - Three Vought O3U-3 Corsairs launched from USS Colorado. Aircraft not damaged. Not a candidate.
Dec. 1, 1938 - Supermarine Walrus launched from HNNZS Leander took aerial photos for the New Zealand survey. Not an American aircraft. Not damaged. Not a candidate.
April 30, 1939 - Grumman J2F Duck launched from USS Pelican took aerial photos for the Bushnell survey. Aircraft not damaged. Not a candidate.
June 20, 1941 - Six Consolidated PBY2 aircraft took aerial photos for a strategic survey. Aircraft not damaged. Not a candidate.
That's it for pre-war aviation in the region.
During WWII the only pre-war type based at Canton Island were two Douglas B-18s. No record of what became of them but there is no accident report either. The B-18 was basically a bomber version of the DC-3. I've inspected the B-18 in the USAF museum collection. Big airplane. No #3 rivets. Not a candidate.
In short, there are no known candidates other than the Lockheed 10 that is known to have been lost in the region.
We need to document when #3 rivets stopped being used for primary structure.
"...the practice of rivet sizing would lie with the airframer (in this case, Lockheed - unless this part is from another maker)."
Wouldn't rivet sizing be governed by Bureau of Air Commerce regs?
I thought so and looked at the old Air Commerce guidance and regs, couldn't find a direct reference. A look at the more modern AC 65-15A (same as 65-15 in this regard but for large airplanes) gives a formula that makes sense (
ref: AC 65-15A Section 5, page 128):
"The size of rivets for any repair can be determined by referring to the rivets used by the manufacturer in the next parallel rivet row inboard on the wing, or forward on the fuselage. Another method of determining the size of rivets to be used is to multiply the thickness of the skin by three and use the next larger size rivet corresponding to that figure. For example, if the skin thickness is 0.040 in., multiply 0.040 by 3, which equals 0.120; use the next larger size rivet, 1/8 in. (0.125 in.)."
Of course the manufacturer can design as they will, short of an outright rule about this sort of thing. I don't think that exists - don't know of it, just 'guidance' - which is binding in the absence of other data, and typically consistent with 'best practices'/what is typically done by designers. What an airframer typically does is meet the overall static strength, damage tolerance, fatigue and aero-elastic qualities, etc. required for structures by employing details that are not, themselves, always directly governed by hard rule.
By the way, the strength of a 2117T 3/32" rivet in single-shear is about 186 pounds per 'Figure 2' on that page as cited above - probably about the same for the old brazier head style. Tension failure would occur at about 60% of that value (ductile modus) - or at around 111.6 pounds of tension. If all those let go at once (excluding the 'keel' row of large fasteners for illustration) you are looking at around 7000 pounds of total force to fail all the 3/32" rivets in unison (does not consider the outer rows / larger rivets); if what we're seeing of that panel is around 275 square inches, that would come to around 25 PSI or so. If that accounted for the fractures we see (are they all brittle failure, or is there evidence of cyclic fatigue failure, i.e. repetitive bending until failure along one or more edges?) then one should add a value for the tensile strength of the skin, not to mention the addtional and larger fasteners.
I can think of a bunch of experiments to screw around with to get an idea of how this thing failed. It would be interesting to understand more about the apparent 'explosive' evidence of bulging, etc. but it is hard to imagine how even a raging sea would distort that much metal. I can readily see the sea 'worrying' the piece off after some initial damage, maybe even fastener-by-fastener, and then failing the remaining edge rivets or fracturing the metal to separation.
Anyway, interesting and there are tons of possiblities.